Add a simple gRPC benchmark. (#51)

This is likely not a very good benchmark (in particular, it somewhat unrealistically introduces client/server contention when recording stats) but provides a starting point for profiling.

Author: Ian Sturdy

opencensus/plugins/grpc/BUILD

@@ -74,3 +74,25 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+# Benchmarks
+# ========================================================================= #
+cc_binary(
+    name = "grpc_plugin_benchmark",
+    testonly = 1,
+    srcs = ["internal/grpc_plugin_benchmark.cc"],
+    copts = TEST_COPTS,
+    linkopts = [
+        "-pthread",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":grpc_plugin",
+        "//opencensus/plugins/grpc/internal/testing:echo_proto",
+        "//opencensus/stats",
+        "@com_github_grpc_grpc//:grpc++",
+        "@com_google_absl//absl/base",
+        "@com_google_absl//absl/strings",
+        "@com_google_benchmark//:benchmark",
+    ],
+)

opencensus/plugins/grpc/internal/grpc_plugin_benchmark.cc

@@ -0,0 +1,116 @@
+// Copyright 2018, OpenCensus Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdlib>
+#include <string>
+#include <thread>  // NOLINT
+
+#include "absl/base/call_once.h"
+#include "absl/strings/str_cat.h"
+#include "benchmark/benchmark.h"
+#include "include/grpc++/grpc++.h"
+#include "opencensus/plugins/grpc/grpc_plugin.h"
+#include "opencensus/plugins/grpc/internal/testing/echo.grpc.pb.h"
+#include "opencensus/stats/stats.h"
+
+namespace opencensus {
+namespace {
+
+absl::once_flag once;
+void RegisterOnce() { absl::call_once(once, RegisterGrpcPlugin); }
+
+class EchoServer final : public testing::EchoService::Service {
+  ::grpc::Status Echo(::grpc::ServerContext* context,
+                      const testing::EchoRequest* request,
+                      testing::EchoResponse* response) override {
+    if (request->status_code() == 0) {
+      response->set_message(request->message());
+      return ::grpc::Status::OK;
+    } else {
+      return ::grpc::Status(
+          static_cast<::grpc::StatusCode>(request->status_code()), "");
+    }
+  }
+};
+
+// An EchoServerThread object creates an EchoServer on a separate thread and
+// shuts down the server and thread when it goes out of scope.
+class EchoServerThread final {
+ public:
+  EchoServerThread() {
+    ::grpc::ServerBuilder builder;
+    int port;
+    builder.AddListeningPort("[::]:0", ::grpc::InsecureServerCredentials(),
+                             &port);
+    builder.RegisterService(&service_);
+    server_ = builder.BuildAndStart();
+    if (server_ == nullptr || port == 0) {
+      std::abort();
+    }
+    server_address_ = absl::StrCat("[::]:", port);
+    server_thread_ = std::thread(&EchoServerThread::RunServerLoop, this);
+  }
+
+  ~EchoServerThread() {
+    server_->Shutdown();
+    server_thread_.join();
+  }
+
+  const std::string& address() { return server_address_; }
+
+ private:
+  void RunServerLoop() { server_->Wait(); }
+
+  std::string server_address_;
+  EchoServer service_;
+  std::unique_ptr<grpc::Server> server_;
+  std::thread server_thread_;
+};
+
+void BM_E2eLatencyCensusDisabled(benchmark::State& state) {
+  EchoServerThread server;
+  std::unique_ptr<testing::EchoService::Stub> stub =
+      testing::EchoService::NewStub(::grpc::CreateChannel(
+          server.address(), ::grpc::InsecureChannelCredentials()));
+
+  testing::EchoResponse response;
+  for (auto _ : state) {
+    testing::EchoRequest request;
+    ::grpc::ClientContext context;
+    ::grpc::Status status = stub->Echo(&context, request, &response);
+  }
+}
+BENCHMARK(BM_E2eLatencyCensusDisabled);
+
+void BM_E2eLatencyCensusEnabled(benchmark::State& state) {
+  RegisterOnce();
+
+  EchoServerThread server;
+  std::unique_ptr<testing::EchoService::Stub> stub =
+      testing::EchoService::NewStub(::grpc::CreateChannel(
+          server.address(), ::grpc::InsecureChannelCredentials()));
+
+  testing::EchoResponse response;
+  for (auto _ : state) {
+    testing::EchoRequest request;
+    ::grpc::ClientContext context;
+    ::grpc::Status status = stub->Echo(&context, request, &response);
+  }
+}
+BENCHMARK(BM_E2eLatencyCensusEnabled);
+
+}  // namespace
+}  // namespace opencensus
+
+BENCHMARK_MAIN();